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Crogge |
2011-12-06
, 01:54
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Joined on Feb 2010
@ Germany
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#91
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Originally Posted by snowparang
How is that possible? The N8 videos have such a high bitrate?
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2011-12-06
, 02:28
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Joined on Oct 2009
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#92
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Originally Posted by snowparang
Read through the *entire* thread, it's worthwhile for a bit more perspective.
Another shocker for me....
The 720p videos taken using my N8 camera cannot be played back smoothly on my N9.
Seriously?
With all this limitations, the N9 is feeling...like a f%(*&*@& iphone!!! ARGGHHH!!
Disappointment with Nokia is an understatement.
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2011-12-06
, 17:05
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Joined on Dec 2010
@ Dayton, Ohio
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#93
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For the "tl;dr" crowd, I'll just give a summary of the problem, rather than force them to read the whole thread. 
However, please note that the N8 has a screen resolution of 640 x 360 pixels. You may be able to play HD resolution videos on the thing, but you sure as heck ain't going to be seeing the higher resolution.
Almost no phone exists that has a native HD resolution screen. (I have been informed that the HTC Rezound has a full 720p screen, so there are some phones that do...) Most phones that can display HD video are simply "throwing away" the extra bits of resolution in order to fit the video onto the screen.
You can, of course, reduce the resolution of a video yourself, using a wide variety of tools. (And these tools will almost always produce a higher quality result than a phone trying to do the same thing in real time.) Many of the posts above in this thread describe how to do this.
Originally Posted by snowparang
The 720p videos taken using my N8 camera cannot be played back smoothly on my N9.
Originally Posted by Crogge
No, the N9 does not play HD resolution video very well, if at all. Those phones which do play HD resolution video are using specialized hardware specifically designed to deal with HD data.
How is that possible? The N8 videos have such a high bitrate?
However, please note that the N8 has a screen resolution of 640 x 360 pixels. You may be able to play HD resolution videos on the thing, but you sure as heck ain't going to be seeing the higher resolution.
Almost no phone exists that has a native HD resolution screen. (I have been informed that the HTC Rezound has a full 720p screen, so there are some phones that do...) Most phones that can display HD video are simply "throwing away" the extra bits of resolution in order to fit the video onto the screen.
You can, of course, reduce the resolution of a video yourself, using a wide variety of tools. (And these tools will almost always produce a higher quality result than a phone trying to do the same thing in real time.) Many of the posts above in this thread describe how to do this.
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2011-12-06
, 17:27
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Posts: 25 |
Thanked: 31 times |
Joined on Feb 2010
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#94
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Originally Posted by Copernicus
Update: the OMAP3630 use the PowerVR SGX530 GPU, not the Mali400 GPU. Sorry for the mistake.
I understand your pain, but I still gotta disagree. Here are my arguments:
...
C - This also means that those phones actually are doing the equivalent of re-encoding the video, only without giving you any say in the quality of the result.
You only need to decode at the resolution of the file. The picture resize at the decoding output is usually assisted by the hardware. On the OMAP3 SoC, you can use the PowerVR SGX530, the DSP, or the picture processing subsystem to do picture resize. The PowerVR SGX530 should be the best choice. You can see how smooth the transitions are on the N9 by using it. A number of transitions includes a resize if the application image buffer in real time. You can use the same for the video output picture buffer.
So the only real limitation is how fast is the decoder to fill the video output picture buffer depending on the resolution of the file.
Last edited by jcdr; 2011-12-06 at 18:42.
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2011-12-06
, 17:46
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Posts: 1,986 |
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Joined on Dec 2010
@ Dayton, Ohio
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#95
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Originally Posted by jcdr
I'm no expert, but I'm fairly certain that the entire decoding process is in fact hardware-assisted. The CPUs in these phones just can't manage the decode fast enough to supply the video data in real time, even for fairly low resolution video, unless perhaps the bitrate is miserably low. (The VLC guys completely gave up trying to port their software-based decoder onto the N900, and I think it was pretty much for that reason.)
You only need to decode at the resolution of the file. The picture resize at the decoding output is usually assisted by the hardware.
I don't know much of anything about the N9's innards. But, unless the "Mali400" is already a part of the N9's video decoding subsystem, you're not going to be able to use it for videos. The silicon tasked with that job can't be changed.
But yeah, I was kinda glossing over the actual process these phones run by saying that it was the "equivalent of re-encoding" the video.
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2011-12-06
, 18:04
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#96
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Not sure where he's getting MALI400 from, 3630 most certainly doesn't use that.
There's some decent insights (not full) into the hw (& it's limitations) just a few pages back peeps.
There's some decent insights (not full) into the hw (& it's limitations) just a few pages back peeps.
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2011-12-06
, 18:38
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Posts: 25 |
Thanked: 31 times |
Joined on Feb 2010
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#97
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Originally Posted by Copernicus
Oops, I made a mistake, the OMAP 3630 (N9 processor) integrate the PowerVR SGX530 GPU, not the Mali400. Sorry for the mistake. Indeed, this is just an other GPU well capable to do picture resize in real time.
I'm no expert, but I'm fairly certain that the entire decoding process is in fact hardware-assisted. The CPUs in these phones just can't manage the decode fast enough to supply the video data in real time, even for fairly low resolution video, unless perhaps the bitrate is miserably low. (The VLC guys completely gave up trying to port their software-based decoder onto the N900, and I think it was pretty much for that reason.)
I don't know much of anything about the N9's innards. But, unless the "Mali400" is already a part of the N9's video decoding subsystem, you're not going to be able to use it for videos. The silicon tasked with that job can't be changed.
But yeah, I was kinda glossing over the actual process these phones run by saying that it was the "equivalent of re-encoding" the video.
Decoding and resizing are different parts of the process of displaying a movie file. Don't mix the two.
Decoding can be done by the CPU or by the DSP. The DSP is probably the best choice, but the community (or company) willing to code it is very limited compared to the CPU community.
Last edited by jcdr; 2011-12-07 at 00:16.
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2011-12-06
, 18:40
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Posts: 25 |
Thanked: 31 times |
Joined on Feb 2010
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#98
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Originally Posted by jalyst
Yes, you are right. The OMAP3630 integrate the PowerVR SGX530 GPU, not the Mali400 GPU
Not sure where he's getting MALI400 from, 3630 most certainly doesn't use that.
There's some decent insights (not full) into the hw (& it's limitations) just a few pages back peeps.
And I am pretty certain that the GPU is heavy used on the N9.
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2011-12-06
, 19:05
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Posts: 112 |
Thanked: 92 times |
Joined on Nov 2010
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#99
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n8 records at 720p AVC baseline profile, 15 mbps!, thats thanks to a dedicated brodcom(as i recall) hw accellarator, no neither my n900 could play it smoothly due to the avc high bit rate, though it now has 720p support.
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2011-12-07
, 01:40
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Posts: 40 |
Thanked: 12 times |
Joined on Dec 2011
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#100
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Originally Posted by Copernicus
Tks for the reply. I did go through the whole thread though my lack of technical knowhow on mobile processors and GPU etc may not allow me to appreciate everything here. I do understand that I am not looking at 720p but a smaller resolution when I watch videos on a screen of a phone. However, I also do know that the actual quality of the video is better than the one I'm seeing on the phone's screen and thus I am satisfied.
For the "tl;dr" crowd, I'll just give a summary of the problem, rather than force them to read the whole thread.
No, the N9 does not play HD resolution video very well, if at all. Those phones which do play HD resolution video are using specialized hardware specifically designed to deal with HD data.
However, please note that the N8 has a screen resolution of 640 x 360 pixels. You may be able to play HD resolution videos on the thing, but you sure as heck ain't going to be seeing the higher resolution.
Almost no phone exists that has a native HD resolution screen. (I have been informed that the HTC Rezound has a full 720p screen, so there are some phones that do...) Most phones that can display HD video are simply "throwing away" the extra bits of resolution in order to fit the video onto the screen.
You can, of course, reduce the resolution of a video yourself, using a wide variety of tools. (And these tools will almost always produce a higher quality result than a phone trying to do the same thing in real time.) Many of the posts above in this thread describe how to do this.
But here's my take (and I assume other 'common users') on the issue....
The N8 is a phone released in Oct 2010. It has a 680 Mhz CPU. It runs on the 'legacy' Symbian OS. As of right now, the telcos in my country has stopped selling it.
1 year later, the N9 is released. It has a 1 Ghz CPU (similiar or even faster than iPhone 4 as I recall). It carries the tagline 'fluidity'. I think as a consumer, it would not be unreasonable to assume that the N9 have the same if not better media capabilities than the N8. For example, the N9's photo gallery is definitely much faster than the N8.
Sure, we can re-encode ('recode'?) the videos to ensure smooth playback on the N9. But aren't we losing details and getting a more compressed video? In other words, we COMPROMISE. Maybe readers may wonder why am I so hardup over the videos, I can just store them on my pc and watch them there. Yes, true, but for me when I transit between phones, I bring over ALL my photos and videos (my N8 has all the photos and videos from my N95). It is a very interesting 'blog', as it captures all my happy and most treasured memories, on a device that I bring along everywhere I go and it will continue to capture the memories in years to come.
Will update on what's the bitrate/resolution of the '720p' video taken by the N9 camera and how much difference is that compared to the N8.
I really do hope this is just a software optimisation issue and not really a hardware limitation.